Loading dock levelers are commonly used for providing an inclined ramp or a level bridge between the surface of a transport truck deck and the floor surface of a loading dock of a building thereby facilitating the loading and unloading of the truck by wheeled vehicles, as well as pedestrian or animal traffic if necessary.
Transport trucks have load carrying decks that vary in height above the pavement depending on the size of truck, the intended use of the truck and the state of compression that the truck suspension is in when loaded or unloaded. Since any truck arriving at a dock may have a deck within a range of heights and the height can float with the suspension under loading, the loading dock leveler must be able to move vertically and the outside end often pivots from a fixed pivot point on the building to rest on the top surface of the truck deck.
The movable deck of the dock leveler usually has a main deck that pivots from the building and an outside lip plate that is thin and of relatively short length that pivots on the outside end of the main deck to provide a smooth transition between the truck deck surface and the main deck. The main deck is a larger thicker structure that provides a long ramp or bridge section to accommodate most of the difference in heights between the truck deck and building floor while the lip plate can be a relatively thin plate that rests upon the truck deck and provides a short ramp transitioning between the truck deck and the dock leveler main deck platform.
Actuators for moving the deck of the dock leveler can include inflatable air bags, hydraulic or pneumatic cylinders, mechanical linkages, cable hoist devices or electric motor driven screw actuators.
In many environments the use of hydraulic oil is not acceptable due to the risk of contamination by oil leaks, health or other safety concerns. For example in food or drug processing, handling or distribution facilities the use of pressurized air actuators are chosen eliminate the risk of contaminating these consumable products with leaked oil.
Further, when loading docks are fitted with load levelers in hospitals, schools, or shopping malls use of air actuators may be preferred for improved hygiene and appearance. Since loading docks are often critical to the operation of a facility with timely movement of supplies and perishable products passing over the dock, any design feature that can simplify maintenance and speed up repairs is highly desirable.
The present invention includes a load leveler mechanism having an air power actuator and also including operating elements that improve performance, simplify manufacturing and maintenance.
Features that distinguish the present invention from the background art will be apparent from review of the disclosure, drawings and description of the invention presented below.